California Code, Public Contract Code - PCC § 20674

(a) Cash.

(b) A cashier's check made payable to the public entity.

(c) A certified check made payable to the public entity.

(d) A bidder's bond executed by an admitted surety insurer, made payable to the public entity.

Any bid may be withdrawn at any time prior to the time fixed in the public notice for the opening of bids by written request for the withdrawal of the bid filed with the public leaseback corporation. The request shall be executed by the bidder or the bidder's duly authorized representative. The withdrawal of a bid does not prejudice the right of the bidder to submit a new bid. Whether or not bids are opened exactly at the time fixed in the public notice for opening bids, a bid shall not be received after that time.

Upon an award to the lowest bidder, the security of an unsuccessful bidder shall be returned in a reasonable period of time, but in no event shall that security be held by the public entity beyond 60 days from the time the award is made.